I actually did a post about Macaulay / Macauley on what used to be my primary blog a year ago where I attempted to find out what caused the name to spike in 1995 (I had to use other data for that). You can read more on:
https://maybeitisdaijirou.wordpress.com/2017/07/15/the-1995-british-macaulaey-spike/
To the other questions, right now, I'm a bit iffy on that name, but I would prefer the 'e' spelling over the 'a', mainly because I do feel that Macaulay is a bit too associated with the actor.
My PNL:
http://www.behindthename.com/pnl/149249'Maybe It Is Daijiro (aka
Maks)' blog:
https://maybeitisdaijirou.wordpress.com/'Beyond
Sakura and
Hiroshi' blog:
https://beyondsakuraandhiroshi.wordpress.com/